Rock drill feeding means



2 Sheets-Sheet 1 April 28, 1936. w. NOBLE ROCK DRILL FEEDING MEANS Filed April 27, '1935 [zwmm aw: Warmm @i mi I w. NOBLE ROCK DRILL FEEDING MEANS Filed April 27, 1935 2 Sheets-Sheet 2 I I n l m 5 y MN w n m A d w fl l w m. a 9.5

8 F i g'lll 11], I 1 :1 Wu? Patented Apr. 28, 1936 UNITED STATES PATENT OFFICE ROCK DRILL FEEDING MEANS Massachusetts Application April 27, 1935, Serial No. 18,634

11 Claims.

This invention relates to a means for feeding by pressure fluid rock drills or other mechanism requiring axial advances, and is specifically directed to the construction of a feeding device which shall be as directly as possible connected to the rock drill, have a minimum overall length consistent with the total length of feed and embody simplicity of construction with self-adjustment.

Briefly, from one major aspect it consists of a piston which may be of any convenient form directly attached to the body of the rock drill to be fed, to which a flexible strip is attached in such a way as to provide adequate sealing against pressure escape along the slot accommodating the travel of the root of the rock drill. Hitherto, pressure feeding devices have been distinguished by the characteristic of a varying length, due to the necessity for telescoping the active elements. In the design under consideration, telescoping is entirely avoided, and the overall length involved for any specific travel may actually be less than with any other known method. Moreover, the feeding effort is directly from the feed cylinder piston to the drill and the sealing strip is without load other than that imposed by its own friction. The mechanism may aptly be likened to a cylinder with a movable Wall.

An object of this invention is to provide an improved feeding means embodying the above characteristics whereby a relatively long travel is attained by means of an extremely compact feeding device. Another object is to provide an improved rock drill feeding means wherein the overall length of the feeding device remains unchanged during the feeding operation, the improved feeding means being so designed as to avoid the necessity for telescoping the active feeding elements. Yet another object is to provide an improved pressure fluid actuated feeding device of the cylinder and piston type having improved means for connecting the rock drill to the active feeding element and having associated therewith improved sealing means whereby a feeding device having the compactness stated above is obtained. These and other objects and advantages of the invention will, however, herein'after more fully appear.

In the accompanying drawings there is shown for purposes of illustration one form which the invention may assume in practice.

In these -drawings,-

Fig. l is a View in longitudinal section through the illustrative embodiment of the improved rock drill feeding means, the associated rock drill being partially shown in elevation to facilitate illustration.

' Fig. 2 is a horizontal sectional view, with parts shown in plan, taken substantially on line 2--2 of Fig. 1.

Fig. 3 is a detail sectional view showing the feed piston and its associated passage means, the feed cylinder being shown in horizontal section.

Fig. 4 is a cross sectional View taken on line 4-4 of Fig. 1.

Fig. 5 is a cross sectional View taken substantially on line 5-5 of Fig. 1, with internal motor parts omitted.

Fig. 6 is a cross sectional view taken substantially on line 6-45 of Fig. 1.

Fig. 7 is a detail sectional View taken on line l-l of Fig. 6.

Fig. 8 is a detail sectional view taken on line 88 of Fig. 6.

Fig. 9 is a detail sectional view taken on line 9-9 of Fig. 6, showing the feed control valve in a different position.

In this illustrative embodiment of the invention there is shown a rock drill generally designated I conventional in form and herein of the pressure fluid actuated hammer type comprising a cylinder 2 having a piston chamber 3 containing a reciprocable hammer piston for delivering impact blows to the shank of a drill steel 4. The drill cylinder 2 has formed on its bottom surface lateral guides 5, 5 slidably mounted in longitudinal guideways 6, 6 on the cylinder 1 of the improved feeding device generally designated 8. The guideways 6 are formed by top plates 9, 9 and a spacing plate J 0 suitably shimmed and secured by bolts II to longitudinal flanges l2 formed on the sides of the feed cylinder 1 throughout the entire length of the latter. The cylinder 1 is mounted on a base plate l3 extending the entire length of the feed cylinder and having a bottom trunnion support M adapted to be mounted in the saddle mounting of a suitable support. The spacing plate It is truly flat as to its under surface and has symmetrical with its axis a closed slot l5 running substantially its full length. Within this slot the lateral guides 5 move and screws I6 extending through the slot secure the rock drill cylinder 2 rigidly and directly to a feed piston IT. This feed piston is herein pereferably of rectangular cross section and is free to slide in a correspondingly shaped bore 18 of the feed cylinder 1. Above the rectangular feed piston l1 and beneath the guide plate 10 lies a flexible strip 19 for maintaining the slot 15 sealed irrespective of the position of the feed piston with respect to the cylinder. This sealing strip is flat, of constant cross section, highly flexible and preferably made of spring steel. The screws 16 passsing through openings in the strip [9 into connection with the drill motor cylinder provide an anchorage for this strip, causing it to move directly with the feed piston. In this instance, the flexible strip I9 is slightly wider than the major dimension of the cylinder bore l8 and is snared between the plate l and longitudinal ledge-iike shoulders 25 formed on the feed cylinder in such a way as to provide freedom for the travel of the strip at either edge, although guiding it firmly. The ends of the cylinder bore 18 are closed by multi-part front and rear heads 2| and 22 secured to the cylinder by bolts 23, and these heads are provided with arcuate channels 24; and the flexible strip passing through these channels is constrained to bend back upon itself in an easy curve, and its lower run lies in a longitudinal passage 25 beneath the base wall of the cylinder, being housed by the bottom trunnion plate 13. The longitudinal slot or passage 25 formed for the strip return is of such cross section and width as to provide complete freedom for the strips travel, and the dimensions of the cylinder as well as the thickness of the strip are selected with care in order to make sure that no excessive fibre stress is set up from the strip material by reason of the return bends. A familiar example of such a flexible strip and the nature of a return bend made in it is furnished by the type of steel measure coiled interiorly of a circular container, to be found in almost every mechanically interested establishment.

As illustrated, secured to the inner sides of the heads 2!, 22 and projecting within the ends of the cylinder bore is are plates 21 carrying cup packings 28 fitting the inner walls of the cylinder bore to prevent leakage from the ends of the cylinder past the heads. Secured to the ends of the feed piston 11 are similar packings 29 for preventing leakage of pressure fluid past the feed piston. It will be observed that at the end plates 21 only that lip of the packing against the strip is called upon to deal with motion, whereas at the piston surfaces three of the packing lips are called into service where they slidingly contact with the walls of the cylinder bore. In action the reactance of the feeding pressure is directly against the piston and so to the sliding rock drill so the only stress in the sealing strip is that imposed by its own friction when subjected to the pressure in the cylinder, crowding it at its lateral edges against the surfaces of the guide base [5, plus a negligible load due to bridging the slot. The staunchness of such a construction against pressure fluid leakage is primarily one of workmanship, since the interstice necessarily left between the edge of the strip and its guideway cannot be definitely packed. The usual difficulty of packing a right-angled corner, necessarily in this case without fillet, of course is present, but the moulding of packing has progressed to a point where these difficulties, under modern conditions, are vastly less than heretofore. The operating necessity for some leakage from such a feed cylinder, if even forward urge is to be achieved, is a favorable circumstance. The probability of slight leakage is therefore entertainable with equanimity. For the sealing of the strip against the guide plate 10, excellent conditions obtain, and the necessity for a flexible strip in order to make the end turns materially enhances the probability of securing staunchness to the slot through which the connection to the rock drill passes.

Suitable pressure fluid passages 33 and 3| are formed in the rear head of the rock drill motor, and these passages are communicable respectively, as hereinafter described, with forward and reverse feed passages 32 and 33 formed in the feed piston l1, and these latter passages extend respectively to the opposite faces of the feed piston through passages 34 and 35, eventually issuing to the cylinder bore through drilled holes in the attachment screws for the feed piston packings 29.

Referring to the feed regulating means shown in Figs. 6, '1, 8 and 9, it will be noted I have illustrated as one possible feed control mechanism an apparatus more fully illustrated and disclosed in Patent No. 2,015,678, granted Oct. 1, 1935. Obviously any other suitable control could be used. It will be observed that pressure fluid flows from any suitable source of supply through an inlet connection 35 into a bore 31 formed centrally in a main throttle valve 38 rotatably mounted in the rear head of the rock drill motor. The wall of this throttle valve is traversed by a radial passage 39 connecting the bore 31 with a circumferentially-extending groove 40 on the exterior valve periphery. Also formed on the exterior valve periphery in the same transverse plane as the groove 45 is a circumferentially extending groove 45. Also formed on the exterior periphery of the valve are circumferentially-extending grooves 42 and 43 (see Fig. 8), the former being communicable with an axial bore 44 in the valve communicating with the bore 31, through a radial passage 45. Arranged transversely of the rear motor head of the rock drill is a bore 46 having mounted therein a rotary feed control valve 41. Connecting the throttle valve bore with the bore 46 of the feed control valve and lying in the planes of the sets of grooves 40, 4| and 42, 43 respectively, are the passages 3| and 30, while lying in the same planes as these passages and grooves, as shown in Figs. 7 and 8, are exhaust ports 48 and 49. The passages 30 and 3! are connectible through the feed control valve 41 with passages e and 5| respectively, in turn communicable with the forward and reverse feed passages 32 and 33 respectively. As shown the feed control valve 41 is traversed by a passage 52 and a communicating right angle passage 53 which, when the valve 41 is in the position shown in Fig. 8, connects the passage as with the passage 50. The valve 41 is also traversed by a passage 54 communicable with an axial passage 55, in turn communicable through a radial passage 56 with the passage 3!, and a radial passage 51 with the passage 51, as shown in Fig. '1. As shown in Fig. 9, arranged parallel with the valve bore 46 is a passage 58 communicable, when the valve 41 is in the position shown in Fig. 8, through a passage 59 with the passage 52. When the valve 41 is in the position shown in Fig. 9 the passage 58 is connected through a passage 69 and the transverse passage 54 in the valve 41 with a vent port 6|. The valve 41 is also traversed by a radial passage 62 communicating with the axial passage 55. When the valve is in the position shown in Fig. 9, passage 55 connects the passage 58 to exhaust through the vent port 6!. The valve 41 is also provided with a longitudinal groove 63 on its exterior periphery, and this groove is communicable with the passage 38 and communicates with passage 54. Also formed in the valve 41 is a longitudinal groove I 54 communicating with the passage 52 and com municable with passage 6|.

From the foregoing description it will be evident that when the throttle valve 38 and feed control valve 41 are in the position shown in Fig. 6, pressure may flow through the inlet connection 36, through the valve bore 31, bore 44, passage 30, passage 52 in the valve 41, passages 59, 50 and the forward feed passage 32 which communicates with the feed cylinder bore at the rear side of the feed piston. At the same time the forward end of the feed cylinder bore is connected to exhaust through the reverse feed passage 33, passages 51, 55, 56, 3|, groove 4| and exhaust passage 48, and as a result the rock drill is fed forwardly along the feed cylinder guideways. When the throttle valve is rotated into its reverse feeding position, pressure fluid may then flow through the radial passage 39, groove 40, passages 3|,'56, 55 and 5| to the reverse feed passage 33 which communicates with the feed cylinder bore at the forward side of the feed piston, while the feed cylinder bore in the rear side of the feed piston is simultaneously connected to exhaust through passages 32 and 50, groove 43 on the throttle valve, and vent passage 49, and as a result the rock drill is fed rearwardly along the feed cylinder guideways. The forward feed passage 32 may be connected to exhaust at will during the forward feeding operation simply by rotating the feed control valve 41 to the position shown in Fig. 9 to connect the passage 50 to exhaust through passages 58, 60, 54 and BI. When the valve is in this position the flow of pressure fluid to the passage 32 is cut off by the valve 41. If it is desired to connect the reverse passage 33 to atmosphere during the reverse feeding operation, the valve 41 may be turned to connect the passage 5| with the passage 62, bore 55, passage 54 and vent port 6|. At this time the communication between the supply passage 3| and passage 5| is out 01f by the valve 41. A quick reverse during feed in either direction may be obtained by other adjustments of valve 41, but as this is fully r described in the patent mentioned, and as this particular feed control structure does not specifically enter into this invention, being merely illustrative of any suitable control, further description is here considered unnecessary.

As a result of this invention it will be noted that an improved rock drill feeding means is provided having a minimum overall length consistent with the total length of feed and embodying simplicity of construction and self-adjustment. It will further be noted that an improved cylinder and piston type feeding device is provided for a rock drill wherein the rock drill is connected directly to the feed piston, thereby eliminating all complicated connections between the feeding means and the rock drill. Other uses and advantages of the improved feeding means will be clearly apparent to those skilled in the art.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a rock drill feeding mechanism, a feed cylinder having a longitudinal slot substantially coextensive with its bore, a feed piston reciprocable in the cylinder bore and to which a rock drill to be fed is adapted to be directly connected, and a flexible sealing strip movable with said feed piston for always maintaining said slot sealed.

2. In a rock drilling mechanism, a feed cylinder having a longitudinal slot extending substantially coextensively with its bore, a feed piston reciprocable in said bore and adapted for connection to a rock drill, and means movable with said feed piston for always maintaining said slot tightly sealed.

3. In a rock drill mechanism, a feed cylinder having a longitudinal slot extending substantially coextensively with its bore, a feed piston reciproc-able in said bore and adapted for connection to a rock drill, and an endless flexible sealing strip having an intermediate portion fixed to said feed piston for always maintaining said slot tightly sealed.

4. In a rock drilling mechanism, a feed cylinder having a longitudinal slot extending substantially coextensively with its bore, end heads for said feed cylinder bore, a feed piston reciprocable in said bore and adapted for connection to a rock drill, and an endless flexible sealing strip having an intermediate portion fixed to said feed piston and end portions guided within said cylinder heads for always maintaining said slot tightly sealed.

5. In a rock drilling mechanism, a feed cylinder having a longitudinal guideway and a longitudinal slot extending substantially coextensively with its bore, a rock drill guided on said cylinder guideway, a feed piston reciprocable in said cylinder bore, a direct connection between said rock drill and said feed piston including a connecting portion extending through said feed cylinder slot, and sealing means secured to said feed piston for maintaining said slot always tightly sealed irrespective of the position of said feed piston in said bore. I

6. In a rock drilling mechanism, a feed cylinder having a longitudinal guideway and a longitudinal slot extending substantially coextensively with its bore, a rock drill guided on said cylinder guideway, a feed piston reciprocable in said cylinder bore, a direct connection between said rock drill and said feed piston including a connecting portion extending through said feed cylinder slot, and sealing means in the form of a flexible sealing element secured to said feed piston for maintaining said slot always tightly sealed irrespective of the position of said feed piston in said bore.

'7. In a rock drilling mechanism, a feed cylinder having a longitudinal guideway and a longitudinal slot extending substantially coextensively with its bore, a rock drill guided on said cylinder guideway, a feed piston reciprocable in said cylinder bore, a direct connection between said rock drill and said feed piston including a connecting portion extending through said feed cylinder slot, and a flexible sealing strip secured to said feed piston for maintaining said slot always tightly sealed irrespective of the position of said feed piston in said bore.

8. In a rock drilling mechanism, a feed cylinder having a longitudinal guideway and a longitudinal slot extending substantially coextensively with its bore, a rock drill guided on said feed cylinder guideway, a feed piston reciprocable in said cylinder bore, means extending through said longitudinal slot for directly connecting said rock drill to said feed piston, and meansmovable with said feed piston for maintaining said cylinder slot always closed irrespective of the position of said feed piston in its bore.

9. In a rock drilling mechanism, a feed cylinder having a longitudinal guideway and a longitudinal slot extending substantially coextensively with its bore, a rock drill guided on said feed cylinder guideway, a feed piston reciprocable in said cylinder bore, means extending through said longitudinal slot for directly connecting said rock drill to said feed piston, and means in the form of a flexible sealing element movable with said feed piston for maintaining said cylinder slot always closed irrespective of the position of said feed piston in its bore.

10. In a rock drilling mechanism, a feed cylinder having a longitudinal guideway and a longitudinal slot extending substantially-coextensively with its bore, a rock drill guided on said cylinder guideway, a feed piston reciprocable in said cylinder bore, means extending through said slot for directly connecting the rock drill to said feed piston, and a flexible sealing strip secured to said piston for always maintaining said slot sealed irrespective of the position of said feed piston in its bore.

11. In a rock drilling mechanism, a feed cylinder having a guideway and a longitudinal slot extending substantially coextensively with its bore, end heads closing said cylinder bore, a rock drill guided on said cylinder guideway, a feed piston reciprocable in said cylinder bore, means extending through said slot for directly connecting the rock drill to said feed piston, and a flexible sealing strip secured to said feed piston for movement therewith and guided with said end heads for always maintaining said slot closed irrespective of the position of said feed piston in its bore.

WARREN NOBLE. 

